if you're having problems with your jaw, braces might not be able to fix that. And when you say that you are constantly having to move it in a "circular" motion to open it & having lock-jaw, that sounds like you'll be needing jaw surgery. uh oh.

but as for the braces themselves, you shouldn't have to wear them for too long. Your teeth are already pretty good so probably a year at most?
my teeth were very janked up (smashed together, one behind the other, etc). I had to wear them for 3 and half years. They were quite painful after the initial placement of the brackets & wire, and everytime i went in to get them tightened. But overall they're not that bad. You get used to them and feel weird when you get them taken off.